WSU Extension

Hortsense

Caption: Spruce budworm
Photo by: T.J. Fitzgerald
  
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Spruce : Spruce budworm
(revision date: 3/8/2016)


Biology
These larvae feed on the buds and foliage and may tie shoot tips together with webbing to make a nest. They are typically green to brown in color with a darker head and grow to approximately 1" long. The adult is a dark gray moth. This insect is an infrequent pest in the landscape. Spruce budworms attack true firs and Douglas fir as well as spruces.
Management Options

Non-Chemical Management
  • It may be possible to hand-pick and destroy budworms on small trees.
  • Natural controls include environmental conditions and parasitic wasps.
Select non-chemical management options as your first choice!

Chemical Management


Apply insecticides in spring (May) when larvae are feeding on old needles and before they enter buds. June to July applications will control larvae on new growth. If Bt is chosen, be sure to apply when insect is feeding. Best time is when caterpillars are young. Use a spreader-sticker with liquid Bt formulations. Horticultural oils, soap-based products and some other products may cause discoloration of spruce needles, particularly on Colorado blue spruce. Read labels carefully and test on a small area before application. Homeowners should not make foliar applications to trees over 10 ft tall. Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bayer Advanced Power Force Multi-Insect Killer R-T-S
    Active ingredient: cyfluthrin  |  EPA reg no: 72155-39
  • Bonide Captain Jack's Deadbug Brew R-T-U [Organic]
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 4-472
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • Safer Brand Caterpillar Killer for Trees, Shrubs & Vegetables Conc II [Organic]
    Active ingredient: Bacillus thuringiensis subsp. kurstaki  |  EPA reg no: 70051-106-42697
  • Safer Brand Caterpillar Killer/Trees, Shrubs, & Vegetables Conc
    Active ingredient: Bacillus thuringiensis subsp. kurstaki  |  EPA reg no: 42697-23
  • This list may not include all products registered for this use.
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Caption: Spruce budworm
Photo by: T.J. Fitzgerald